Plants 40-60 cm tall. Rhizome obliquely ascending, densely scaly; scales ovate-lanceolate, denticulate, ferruginous or pale brown. Fronds approximate; stipe stramineous, ca. 20 cm, base brown, densely scaly; scales brown, ovate-lanceolate, 4-5 × 2-3 mm, entire, acuminate, sparser upward; lamina lanceolate, 13-18 × 5-8 cm, once pinnate-pinnatifid, base truncate, apex acute or acuminate; pinnae spreading, narrowly elliptic, shortly stalked, apex obtuse. Lamina glabrous adaxially, with lanceolate or fibriform brown scales on abaxial side of costa. Sori in 1(or 2) rows on each side of costa; indusia orbicular-reniform, entire.

The type specimen of Dryopteris costalisora, conserved in Kyoto University, bears immature sori. The above description is taken from the protologue.

Forests, roadsides, slopes; 2500-3400 m. Taiwan [NE India, Nepal].